In the test, test with Vec first to see how Rust implements panic
recovery while elements drop. If Vec drops all the elements, then we
test that arrayvec does too.
- Add try_insert / try_remove to be the old fallible variants that
return errors
- Insert that pushes out if full does no longer exist -- full vec is an
error
What the test was doing was simply UB and we can't expect rustc to make
sense of it. The test was failing with optimizations on, yet a closer look
says arrayvec is still working as it should. So remove the broken test.
Previously we used formatting, which is a virtual call and quite the
detour. Now copy the utf-8 encoding code from Rust (thank you Alex
Crichton) and use that.
ArrayVec::drop was not panic safe — if there would be a panic during an
element's drop, the discriminant would never be set to Dropped, and the
array elements would potentially double drop.
Fix this by going back to the old NoDrop composition. The NoDrop struct
thas its own Drop impl, that will trigger too on panic during an element's
drop. This serves to make ArrayVec::drop panic safe.
Also tweak IntoIter::drop to make it panic safe: set inner ArrayVec's
length before dropping any elements.
Thank you to @Stebalien for reporting this bug and providing the
excellent testcases in this commit.
Using NoDrop expands ArrayVec to have two drop flags again, but this
is a temporary tradeoff, drop flags will eventually go away.
Fixes#3
Don't use NoDrop as a separate abstraction: Then we have two drop flags,
one for ArrayVec and one for NoDrop. Instead import the logic from
NoDrop. The result is a much smaller ArrayVec value.
bluss